The bottom line:
As average display sizes continue to increase, and with direct bonding continuing to trend upward, the total adhesive market for mobile phones will grow 8 percent from 20.4 million square meters in 2015 to 22.1 million square meters in 2016.
The market for optically clear adhesives (OCA) used in mobile phones will increase by more than 10 percent per year after 2017, thanks to increasing use of decorative films used for 3D cover lenses, flexible displays and the trend toward more direct-bonding, in which there is an adhesive layer between the touch sensor or cover lens and the display panel.
The optically clear resin (OCR) market for tablet PCs will grow 30 percent in 2016, compared to the previous year, since Apple and Samsung both use OCR in their tablet products and the use of direct bonding for larger displays is rising.
Embedded in-cell and on-cell touch-screen solutions are on the rise, which is changing the touch sensor structures and influencing the use of adhesive materials.
Curved and flexible displays -- featuring 3D cover lenses and decorative film replacing silk-print ink -- influences the adhesive materials used.
Direct bonding is a popular way to make mobile devices thinner and improve display performance.
Background and Definitions:
A touch panel has a maximum of four layers, depending on location and function. Following are definitions for each of the four adhesive functions:
1. Decoration lamination refers to an adhesive layer between the cover lens and the decoration film. Instead of a screen-print solution, Samsung has begun to use a separate decorative film for the cover lens bezel in its Galaxy S3, thereby offering various bezel colors. As for 3D cover lenses, screen-printing is not suitable for curved bezels, so a decorative film is used instead.
2. Cover lens lamination refers to an adhesive layer between the touch sensor and the cover lens. In touch panels with a separate touch sensor layer, such as GFF, GF, GF2, G1F, and GG, cover lens lamination is required. However, in-cell, on-cell, and one glass solution (OGS) touch panels do not have a separate touch sensor layer and do not need cover lens lamination, because there is direct bonding between the cover lens and the display.
3. Sensor lamination is an adhesive layer used to bond two touch sensor layers in touch panels. GFF is the only touch panel that requires sensor lamination.
4. Direct bonding refers to an adhesive layer between the touch panel module or cover lens and the display panel.
Although the demand for cover lens lamination and sensor lamination is declining, rising direct-bonding demand for mobile phones is making up the loss. The functional use of adhesives in direct bonding will account for more than half (51.3 percent) of total area share in 2016, after comprising just 46.2 percent in 2015.
OCA is more suitable than OCR for use in flexible curved displays and 3D cover glass. In addition, vivid decorative film is now replacing the conventional color ink beneath the cover lens, which requires OCA for bonding. Even as smartphones from Samsung and Apple lead growth in the flexible display market in 2017, the demand for decorative film will grow even faster.
Although the overall tablet PC market is declining, Apple, Microsoft and Samsung are now adopting OCR for direct bonding, which is leading to rising OCR demand. In addition, two-in-one tablets with 10-inch displays also use direct bonding.